Kristine Davis, a spacesuit engineer at NASA's Johnson Space Center, wearing a ground prototype of ... [+]
If NASA can transcend today’s fractious and uncertain political climate, there’s no reason that it can’t meet its announced 2024 goal of sending astronauts back to the lunar surface, says astrophysicist Neil deGrasse Tyson.
“If our culture sees NASA as transcending politics, then there’s no reason why we couldn’t be back on the moon in 2024; if NASA is embedded in politics, it takes on a level of uncertainty that’s hard to predict,” Tyson, Director of New York’s Hayden Planetarium, told me by phone.
When President John F. Kennedy said let’s go to the Moon, it was 1961 and the U.S. didn’t yet have a rocket capable of launching humans into space, says Tyson. But eight years later NASA had humans on the Moon, he says. Even so, he notes that historically, it seems hard for a president to create a NASA mission that survives multiple presidencies.
More than a year after our last conversation, Tyson and I spoke again on the occasion of his just published new book, Letters from an Astrophysicist —- his correspondence with people who sought him out for answers on questions spanning science, faith, philosophy, life; even Pluto.
Here is Tyson’s take on some of our talking points.
On whether to send an orbital mission to Pluto?
Every object in the solar system has become more interesting when studied up close than when studied from afar, says Tyson.
NASA’s New Horizons’ Pluto flyby was a resounding success. But Tyson says Pluto remains key to understanding the Kuiper belt, a large band of mostly small icy bodies lying beyond the orbit of Neptune. Thus, an orbital mission to Pluto would enable a spacecraft to hang out there and sustain long-term scientific measurements of what’s going on, he says.
Such a mission, says Tyson, might help planetary scientists better understand: Just how scarred Pluto’s surface really is. Why Charon, its biggest moon, is so relatively large in comparison to Pluto. The extent of its atmosphere. Whether Pluto has seasons. And, if so, how intense are they? And is there anything else that we didn’t know about it that we didn’t even know to ask?
On what the astronomical community should be researching that is isn’t already.
Understanding how we went from organic molecules to self-replicating life needs to be a very high priority in biology, says Tyson. It’s already a priority, but you could up it a few notches, he says.
“That would give us an understanding of how life formed on Earth,” said Tyson. “And maybe it didn’t form on Earth; maybe it formed on another planet.”
Some of the most fertile understandings of the natural world have arisen when you cross-pollinate scientific fields, he says. Are their fields of science that have not fully cross pollinated with astrophysics and astronomy? Tyson wonders. Yes, there is astro-chemistry, bio-geology, astro-particle physics, he notes, but maybe there’s a pairing that we haven’t thought of yet.
On the prospects for detecting biosignatures of life on extrasolar planets?
The idea is simple, but the execution of that idea requires extraordinary technologies, Tyson says. You need a planet that transits in front of its host star where the atmosphere contaminates the spectra in a way that you can then say this is in the star and this is from the planet itself, he says. The atmosphere is the best first pass at this —- short of going there and analyzing soils, he notes.
As mentioned in a 2018 paper appearing the AAAS journal Science Advances, chemical disequilibrium in planetary atmospheres is a proposed method of detecting life remotely via extrasolar planetary spectroscopy of a planetary body’s atmosphere. That’s because as the authors note, life produces waste gases that modify an atmosphere’s composition.
If you find free oxygen or methane in an atmosphere, these are unstable molecules, it’s like ‘hey, let’s keep an eye on this tantalizing evidence for life,’ Tyson says. Within five years, we could detect microbial life in an atmosphere, he says. But there will always be someone casting aspersions on any such putative detections, Tyson notes.
Letters From An Astrophysicist 978-1-324-00331-1
On whether E.T. would already know we’re here?
We’re coming up on an 80 light-year radio-spectrum radius from Earth, says Tyson. So, anyone with radio telescopes within that distance, he says, would see that Earth is a source of radio signals in ways that terrestrial planets without a technological civilization would never be.
If they were ahead of us technologically and they found Earth orbiting the Sun, they would also find all manner of chemical signatures in our atmosphere that would tell them that something was going on, says Tyson.
“I see no reason why they wouldn’t immediately jump to the rational conclusion that there’s life that’s creating it,” said Tyson.
In fact, when the Galileo space probe swooped by Earth in 1990, all its instruments were pointed towards us, says NASA. The late Carl Sagan and colleagues published a 1993 Nature paper arguing that Galileo found clear signs of life during its Earth flyby, NASA notes.
On the structure of the Cosmos itself; or why we evolved on a spherical terrestrial planet circling a burning ball of hydrogen.
We are made of hydrogen, nitrogen, oxygen, and carbon; four of the five most common elements in the Universe, says Tyson. One of the manifestations of gravity gathering things into one place is that it gathers them into round objects with heavy things in the middle, he notes.
“If we were made of rare ingredients on a planet that looked like no other planet could possibly look [circling] a star that was unusual,” said Tyson, “then you’d have a case to say that something special is going on here. But the opposite is true.”
